New Soft Electronics Fabrication Method is a Step Toward DIY Smart Tattoos

Imagine an electronic wearable device, like a Fitbit, stuck on a sticker or temporary tattoo that could read a pulse or measure hand gestures. Then imagine printing that device on your home printer.

Carnegie Mellon University Mechanical Engineering Professor Carmel Majidi, Ph.D. student Eric Markvicka and former postdoctoral fellow Michael Bartlett have created a method to print skin-mountable electronics in a quick and cost-effective way. Their research was published in Advanced Functional Materials.

“One of the remaining challenges in skin-mounted electronics is to interface soft circuits with the rigid microchips and electronics hardware required for sensing, digital processing and power,” Majidi said. “We address this with a breakthrough digital fabrication technique that enables efficient creation of wireless electronics on a soft, water-resistant, medical-grade adhesive.”

Electronics produced from this method contain rigid components that you typically see on a circuit board, such as transistors, microprocessors and power regulators, with soft deformable wiring that stretches and bends.

The method uses commercially available films to create wearable electronics through rapid prototyping and assembly techniques. Using a combination of laser cutting with alignment control, they create individual layers and assemble them through a soft transfer printing technique.

Majidi and his team created a fully functional “data skin” in under an hour. Since the method is based on inexpensive processing tools and materials, the circuits can be produced for less than a dollar.

When wrapped around the fingertip, a “data skin” embedded with an optical pulse oximetry chip can measure heart rate and blood oxygenation, or can bond to the back of the hand to monitor hand gestures. After use, the “data skin” can be painlessly peeled from the skin and discarded.

Because the production is fast and inexpensive, users can create their own highly customizable wearable data skins. This is a big step toward fabrication of customized wearables by non-experts.

“This new and versatile method to print skin-mountable electronics represents a first step toward a fully automated method in which non-experts can create their own customized wearables,” Majidi said. “No longer limited to smartphones and smartwatches, the next generation of personal electronics will be soft, stretchable, and stick to skin or clothing. Moreover, they can be produced at home with an inexpensive printer not unlike a desktop LaserJet.”

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